Background: Cattle are intermediate hosts of six Sarcocystis species, among which Sarcocystis hominis and Sarcocystis heydorni can infect humans through the consumption of raw or undercooked meat. In addition to the zoonotic potential, there is increasing interest in these protozoa due to the evidences supporting the role of Sarcocystis spp. in the occurrence of bovine eosinophilic myositis (BEM), a specific inflammatory myopathy which leads to carcass condemnation and considerable economic losses. Actually, all the prevalence studies carried out on cattle in Italy have been based either on morphological or 18S rDNA-based molecular techniques, most likely leading to misidentification of closely related species. Therefore, there is a strong need for new data on the prevalence of the different Sarcocystis spp. in cattle in Italy and their association with bovine eosinophilic myositis.
Methods: To reach our aim, individual cattle samples from BEM condemned carcasses (N=54) and randomly sampled carcasses (N=59) were obtained from Piedmont slaughterhouses. Genomic DNA was extracted and analyzed by multiplex-PCR targeting 18S and cox1 genes. PCR products amplified using the genus specific primer set in absence of the specific fragment for S. hirsuta, S. cruzi, S. hominis or S. bovifelis, were sequenced to achieve species identification.
Results: Sarcocystis DNA was detected in 67.8% of the samples from slaughter cattle and in 90.7% of the samples from BEM condemned carcasses. S. cruzi was identified as the most prevalent species (61%), followed by S. bovifelis (10.2%), S. hominis (8.5%) and S. hirsuta (1.7%). Notably, among the different Sarcocystis spp. detected, the presence of S. bovifelis and S. hominis was significantly higher in samples isolated from BEM condemned carcasses (46.3% and 40.7% respectively), while there was no statistically significant difference between the presence of S. cruzi or S. hirsuta in BEM condemned carcasses and randomly sampled carcasses. Furthermore, DNA sequence analysis revealed the presence of a putative new species in 2 carcasses.
Conclusions: Our study contributes to update the data on the prevalence of the different Sarcocystis spp. in cattle in Italy and emphasize the role of S. hominis and S. bovifelis as the major sarcosporidian species involved.